Machine for manufacturing packaging bags



y 14, 1964 o. BARTHELMESS 3,140,643

MACHINE FOR MANUFACTURING PACKAGING BAGS Filed Oct. 2, 1962 2 Shets-Sheet 1 FIG. 7

FIG. 2

y 14, 1964 o. BARTHELMESS 3,140,643

MACHINE FOR MANUFACTURING PACKAGING BAGS Filed Oct. 2, 1962 2 Sheets-Sheet 2 FIG. 3

United States Patent 3,140,643 MACHINE FOR MANUFACTURING PACKAGING BAGS Otto Barthelmess, Stuttgart-Bad Cannstatt, Germany, assignor to Fa. Fr. Hesser Maschinenfabrik-Aktiengesellschaft, Stuttgart-Bad Cannstatt, Germany Filed Oct. 2, 1962, Ser. No. 227,901 Claims priority, application Germany Nov. 3, 1961 6 Claims. (Cl. 93-12) This invention relates to machines for manufacturing packaging bags in which a bag blank of heat-sealable material is placed around a folding mandrel and formed into a sleeve by means of a longitudinal seam made by heat sealing together the inner faces of the ends of the blank standing up from the mandrel.

In these machines it is previously known to fold down on the mandrel the two upstanding ends of a blank, which has been applied in U-shape around the mandrel, by means of two heated folding bars which are arranged pivotally above the mandrel, and then to make the longitudinal seam. To ensure that the ends of the blank to constitute the seam are correctly applied together in the required fashion, that is to say inner face against inner face, a stationary guide bar or the like is provided between the pivotable folding bars and deflects the two ends of the blank upwards, during the folding over operation by the folding bars, thereby to bring the inner faces together.

Now experience has shown that, depending on the packaging material used, the finished longitudinal seam may, to some extent, open again when the heated folding bars are removed, due to the inherent stresses in the packaging material; as a consequence the sleeve thereby formed will, at the very least, be found too loosely seated on the mandrel for the subsequent operations to be fully successful.

It is an object of this invention to meet this shortcoming in a simple and expedient fashion.

A further object is to accomplish this aim by means which can be utilized to hasten the seam formation.

' In pursuance of these aims it is proposed to provide the folding mandrel, at a zone adjacent the line of the intended longitudinal seam, with openings through which air can be blown from the interior of the mandrel.

This enables the stationary guide bar to be dispensed with, because the outwardly-directed air flow will so guide the ends of the blank as to ensure that their inner sides are applied face to face. lmportantly, too, there will be a rapid cooling of the longitudinal seam, particularly at the sensitive zone, and the machine output increased in consequence.

Moreover, in accordance with a feature of the invention, the folding mandrel is provided with a longitudinal channel, which connects the outlet ends of the blowing openings along which the emergent air blow can flow from the sides of the openings, when the longitudinal seam is closed, and thus be able better to fulfill its cooling function. In addition, this channel allows the heated folding bars to be brought close to the mandrel, thereby assisting the formation of a neat and intimate tubular sleeve around the mandrel.

Examples of the machine according to the invention are illustrated in the attached accompanying drawings, in which:

3,140,643 Patented July 14, 1964 ice FIGURE 1 is a side View of part of a machine for manufacturing packaging bags, equipped in accordance with this invention.

FIGURE 2 is an elevational view of the part of the machine seen in FIGURE 1.

FIGURE 3 is a side view of a folding mandrel, partly in longitudinal section,

FIGURE 4 is a plan view of the mandrel illustrated in FIGURE 3,

FIGURES 5 to 7 diagrammatically illustrate, in front view, stages in the formation of the longitudinal seam of the bag with the apparatus illustrated in the previous figures, and

FIGURE 8 is a longitudinal section showing a device for controlling the supply of blowing air to the mandrel.

The drawings illustrate the relevant part of a machine for manufacturing packaging bags on folding mandrels, as generally described in United States Letters Patent No. 2,257,689 (Jungmayr). This machine comprises a plurality of folding mandrels 2 radiating from an intermittently rotatable mandrel wheel 1 and passing in turn to the individual operating stations of the machine, for the production of bags, or lining bags with a surrounding carton. The present invention is particularly concerned with the folding mandrels 2 themselves and with that station in the machine in which blanks B are folded into a sleeve around a mandrel 2 and the ends of the blank are bonded together, inner face to inner face, in the formation of a so-called finseal seam.

The blanks B, which are cut off by a cutter device 33, 34, from a web W fed in to the machine intermittently by means of a draw roller pair 31, 32, are folded into U-shape by a folding box having a bottom 3 and two side walls 4. When this folding box is moved upwards, the bottom 3 thereof presses a blank B from below against the folding mandrel 2 which is standing ready at this folding station and the side walls 4, moving up to a higher level, turn over the two outstanding wings of the blank B against the sides of mandrel 2.

A set of upwardly directed blowing nozzles 36 provided in each of the side walls 4 of the box assists this folding procedure, the nozzles of each set being connected to a pipe 35 in turn coupled to a compressed air conduit 37 (see FIGURE 5).

The two ends of the U-folded blank B which have been raised vertically in this way are turned down on to the upper face of the folding mandrel 2 by means of two heated folding bars 5, 6 which are pivotable relatively to one another in pincers fashion.

Each of the folding mandrels 2 is provided, in the region of the line along which the longitudinal seam of the bag or tube is formed, i.e. along its centre line in the case illustrated, with a plurality of openings 7 in the form of holes or slits to which compressed air is supplied from the interior of the mandrel so that they produce a substantially upwardly directed flow of blowing air. This air blow guides the outer parts of the ends of the blank upwardly in the required fashion and has the effect that the complete longitudinal seam is rapidly cooled after the bonding or welding process (FIGURES 6 and 7). Accordingly the air flow must be continued after the formation of the longitudinal seam and be distributed along the length of the seam, and for the latter purpose a longitudinal channel 9 is provided along the upper face of the mandrel with the aforesaid openings 7 connected to it.

The cross sectional shape of channel 9 is moreover such that the heated folding bars 5 and 6 can be brought close to the upper face of the mandrel in their arcuate travel, thereby to ensure that the tubular sleeve formed fits snugly on the mandrel. This last mentioned advantage may, of course, also be achieved with folding mandrels which have no blow openings.

The blowing air is supplied in this assembly in the manner illustrated in FIGURES 1 to 4 of the drawings, viz. through a tube which is a push fit on a pipe 12 passing through a forming block 11. At its other end the pipe 12 has a flexible bush which bears in sealing fashion annularly around the opening of a longitudinal conduit 8 arranged in the folding mandrel 2 and having the blowing air openings 7 diverging therefrom.

The block 11 referred to above has the same cross section as the folding mandrel 2 and assists a neat shaping of the end part of the packaging sleeve or envelope, which projects beyond the folding mandrel 2 and is later to be folded to form the bottom of the bag. The block 11 is mounted for pivoting in the longitudinal plane of the particular folding mandrel 2 which at the time is at the folding station so that, after the sleeve has been formed from the blank B, the block 11 can be retracted away from the end of this sleeve before the mandrel wheel 1 is turned through a further step by the means described in the aforesaid Letters Patent No. 2,257,689.

Advantageously, the control of the supply of blowing air to the longitudinal conduit 8 and to the openings 7 in the folding mandrel 2 can be coordinated with the movement of the forming block 11 relatively to the end face of the mandrel 2 concerned. Thus this block may in this case (see FIGURE 8) have a slide valve comprising essentially an axially slidable control sleeve 15 under the action of a return spring 16. At the end thereof projecting from the block 11, this sleeve 15 has an axial bore provided with a radial aperture 17 which can be brought into register with a vertical duct 18 in the block 11; compressed or blowing air can be passed into the duct 18 from the tube 10 through a pipe element 19 and an associated duct 20 in the block 11, thereby to pass through the aperture 17 into the interior of the control sleeve 15.

The control sleeve 15 is normally projected by the spring 16 sufficiently from the leading face of the block 11 towards the end face of the folding mandrel 2 for an uninterrupted rear part of the sleeve 15 to close the vertical duct 18. When the block 11 is swung against the end face of a folding mandrel, the free end of the control sleeve 15 is applied against the zone of the end face of the folding mandrel at which the channel 8 opens, and as a result of this movement of the block 11, the control sleeve 15 is pushed rearwards against the action of spring 16, thereby to bring the radial bore 17 into register with the vertical duct 18 and allow compressed or blowing air to pass into the channel 8 and out through the openings 7. When the block 11 is swung back the valve closes automatically under the action of spring 16 and so shuts off the flow of compressed or blowing air.

The folding bars 5, 6 are heated by means of electrical heating cartridges 38 and are secured on arms 40 and 41 each of which is arranged on a shaft, 42 and 43 respectively. The shafts 42 and 43 are pivotable in fixed pivots, 45 and 46 respectively, on the machine frame and are coupled together by a suitable linkage to ensure that the folding bars 5, 6 pivot in unison. This linkage comprises levers 47 and 48 connectedto the shafts 42 and 43, and a link 49 interconnecting these levers.

The movement of the folding bars is brought about by a barrel cam 51 mounted on an operating shaft 50, the control movement being transmitted to shaft 43 through a lever 52, a link 53, and a lever 54 on shaft 43.

The pivotal movement of the forming block 11 is implemented by securing this to a double-armed lever 55 which is rotatably mounted on a spindle 56 provided in the machine frame. The periodic automatic rocking is 4 brought about by a camplate 57 which is mounted on the control shaft 50 and acts through a lever 53, a link 59, a bellcrank lever 60 and a bar 61 on the lever 55.

To prevent the blank B, wrapped around the folding mandrel 2 from slipping during the various operating procedures in the machine, suction bores are provided in mandrel 2 so as to open at its upper face and at its two narrow sides. These suction bores 21 are connected with longitudinal ducts 22 in the folding mandrel, and these lead in turn to openings 23 in the hub of the mandrel Wheel 1. Over a part of the travel of the bores 23 they register with a fixed conduit 24 connected to a suction pump (not shown). The blank B, when shaped into a U, and subsequently into a sleeve, on the folding mandrel 2 is held in the requisite position by a suction induced by the suction pump and applied through conduit 24, openings 23, ducts 22 and bores 21.

It will be understood that it is also possible to conduct the compressed air to the openings 7 of the mandrel 2 from the hub of the mandrel wheel through suitable connecting ducts, the control being implemented by shutters or by cam controlled electro-magnetic valves, of known form.

I claim:

1. In a machine for manufacturing packaging bags, assembly for seaming bag blanks comprising at least one folding mandrel, means to convey a blank to and fold it around said mandrel, and heat sealing jaws movable to engage, along a line adjacent a longitudinal zone of said mandrel, the margins of a blank enfolding said mandrel, thereby to form the blank into a sleeve with a heatsealed longitudinal seam, said mandrel having blowing openings along said longitudinal zone and being formed internally with an air distributing ducting communicating with said blowing openings.

2. A bag-seaming assembly as claimed in claim 1, in which a row of blowing openings is formed along the upper face of the mandrel and said openings communicate with a common longitudinal air conduit in the body of the mandrel.

3. In a machine for manufacturing packaging bags, assembly for seaming bag blanks comprising at least one folding mandrel, means to convey a blank to and fold it around said mandrel, and heat sealing jaws movable to engage, along a line adjacent a longitudinal zone of said mandrel, the margins of a blank enfolding said mandrel, thereby to form the blank into a sleeve with a heatsealed longitudinal seam, said mandrel having blowing openings along said longitudinal zone, a channel in the surface of the mandrel along said marginal zone interconnecting said openings, an internal air conduit through its length and ducts connecting said blowing openings to said air conduit.

4. In a machine for manufacturing packaging bags, assembly for seaming bag blanks comprising at least one folding mandrel, means to convey a blank to and fold it around said mandrel, heat sealing jaws movable to engage, along a line adjacent a longitudinal zone of said mandrel, the margins of a blank enfolding said mandrel, thereby to form the blank into a sleeve with a heat sealed longitudinal seam, said mandrel having blowing openings along said longitudinal zone and having internal air distributing ducting communicating with said blowing openings, a forming block adjacent one end of said mandrel and having an air passage therethrough, and means for moving said forming block against said one end of the mandrel to connect said air passage with the said distributing ducting.

5. In a machine for manufacturing packaging bags, assembly for seaming bag blanks comprising at least one folding mandrel, said mandrel having blowing openings along said longitudinal zone, and having internal air distributing ducting communicating with said blowing openings, means to convey a blank to and fold it around said mandrel, heat sealing jaws movable to engage, along a line adjacent a longitudinal zone of said mandrel, the mar- 6 gins of a blank enfolding said mandrel, thereby to form 6. A bag-seaming assembly as claimed in claim 5, in the blank into a sleeve with a heat sealed longitudinal which the shut-off valve is a Sleeve valve comprising a seam, a forming block pivoted adjacent one end of said 'f member whlch Projects from the leadlng end of folding mandrel and having therein an air passage in- Sald formmg block corporating a shut-ofi valve, and means for moving said 5 References Cited in the file of this patent forming block against said one end of the mandrel to con- UNITED STATES PATENTS nect said air passage with said distributing ducting and 1,976,259 Jaime Oct. 9, 1934 open said shut-off valve. 2,966,832 Vergobbi Ja 1961 

1. IN A MACHINE FOR MANUFACTURING PACKAGING BAGS, ASSEMBLY FOR SEAMING BAG BLANKS COMPRISING AT LEAST ONE FOLDING MANDREL, MEANS TO CONVEY A BLANK TO AND FOLD IT AROUND SAID MANDREL, AND HEAT SEALING JAWS MOVABLE TO ENGAGE, ALONG A LINE ADJACENT A LONGITUDINAL ZONE OF SAID MANDREL, THE MARGINS OF A BLANK ENFOLDING SAID MANDREL, THEREBY TO FORM THE BLANK INTO A SLEEVE WITH A HEATSEALED LONGITUDINAL SEAM, SAID MANDREL HAVING BLOWING OPENINGS ALONG SAID LONGITUDINAL ZONE AND BEING FORMED INTERNALLY WITH AN AIR DISTRIBUTING DUCTING COMMUNICATING WITH SAID BLOWING OPENINGS. 